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VIPER35LDTR
STMicroelectronics
IC OFFLINE SWITCH FLYBACK 16SO
10051 Pcs New Original In Stock
Converter Offline Flyback Topology 136kHz 16-SO
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5.0 / 5.0
- (27 Ratings)
VIPER35LDTR
Product Overview
8202272
DiGi Electronics Part Number
VIPER35LDTR-DGManufacturer
STMicroelectronics
VIPER35LDTR
Description
IC OFFLINE SWITCH FLYBACK 16SOInventory
10051 Pcs New Original In Stock
Converter Offline Flyback Topology 136kHz 16-SO
Quantity
Minimum 1
Minimum 1
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VIPER35LDTR Technical Specifications
Category
Power Management (PMIC), AC DC Converters, Offline Switches
Packaging
Tape & Reel (TR)
Series
-
Product Status
Active
Output Isolation
Isolated
Internal Switch(s)
Yes
Voltage - Breakdown
800V
Topology
Flyback
Voltage - Start Up
14 V
Voltage - Supply (Vcc/Vdd)
8.5V ~ 23.5V
Frequency - Switching
136kHz
Power (Watts)
22 W
Fault Protection
Current Limiting, Over Temperature, Over Voltage, Short Circuit
Control Features
-
Operating Temperature
-40°C ~ 150°C (TJ)
Package / Case
16-SOIC (0.154", 3.90mm Width)
Supplier Device Package
16-SO
Mounting Type
Surface Mount
Base Product Number
VIPER35
Datasheet & Documents
HTML Datasheet
VIPER35LDTR-DG
Environmental & Export Classification
RoHS Status
ROHS3 Compliant
Moisture Sensitivity Level (MSL)
3 (168 Hours)
REACH Status
REACH Unaffected
ECCN
EAR99
HTSUS
8542.39.0001
Additional Information
Standard Package
2,500
Reviews
5.0/5.0-(Show up to 5 Ratings)
December 02, 2025
Le suivi de ma commande a été précis et en temps réel, ce qui m'a permis de m'organiser facilement.
December 02, 2025
Clear communication about costs and delivery times enhances customer confidence.
December 02, 2025
Their commitment to quality is evident in every item I have purchased.
December 02, 2025
DiGi Electronics consistently delivers products that meet the highest standards.
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Frequently Asked Questions (FAQ)
When designing a 20W isolated offline flyback power supply for industrial equipment, how does the VIPER35LDTR compare to the Power Integrations TNY290KG in terms of thermal performance and reliability under continuous high-load operation?
The VIPER35LDTR offers superior thermal performance in continuous high-load scenarios due to its integrated 800V avalanche-rated MOSFET and optimized internal layout, which reduces hot-spot formation compared to the TNY290KG’s lower breakdown voltage (700V) and less aggressive thermal design. However, the VIPER35LDTR’s 16-SO package has limited PCB copper area for heat spreading, so you must use a 2 oz copper pour with thermal vias under the device. In contrast, the TNY290KG uses a more thermally conductive eSOP package. For sustained 20W+ loads, the VIPER35LDTR requires careful layout and airflow; otherwise, its over-temperature protection may trigger prematurely, reducing system uptime.
Can the VIPER35LDTR safely replace the ON Semiconductor NCP1072 in a 15W consumer AC-DC adapter, and what design changes are necessary to maintain EMI compliance and startup reliability?
Yes, the VIPER35LDTR can replace the NCP1072, but critical modifications are required. The NCP1072 operates at 65–115 kHz with frequency jitter for EMI reduction, while the VIPER35LDTR runs at a fixed 136 kHz—this increases conducted EMI near the 150 kHz limit, requiring enhanced input filtering (e.g., larger X-cap and common-mode choke). Additionally, the VIPER35LDTR’s startup threshold (14 V) is higher than the NCP1072’s (~10 V), so the startup resistor network must be recalculated to ensure reliable turn-on at low-line (90 VAC) input. Without these adjustments, you risk EMI failures or intermittent startup, especially in brownout conditions.
What are the key risks when using the VIPER35LDTR in a medical-grade isolated power supply, and how can I ensure long-term reliability despite its MSL 3 moisture sensitivity rating?
The primary risks include compromised isolation integrity over time due to moisture ingress and potential latch-up during sterilization cycles. Although the VIPER35LDTR is RoHS3 compliant and REACH unaffected, its MSL 3 rating (168-hour floor life) demands strict handling: components must be baked if exposed >168 hours at >30% RH. For medical applications, you must apply conformal coating after assembly to prevent dendrite growth across the 16-SO pins under high humidity. Additionally, the 800V breakdown provides only 2x margin over typical 300–400V working voltages—insufficient for reinforced isolation per IEC 60601. Use an external reinforced optocoupler and ensure >8 mm creepage on the PCB to meet safety standards.
How does the VIPER35LDTR’s fault protection behavior differ from the Infineon ICE2QR4785G in overload and short-circuit conditions, and what impact does this have on system-level protection design?
The VIPER35LDTR implements hiccup-mode current limiting with auto-restart after fault clearance, which reduces stress on the transformer and input capacitors during repeated short circuits—ideal for field-replaceable units. In contrast, the ICE2QR4785G latches off on overcurrent, requiring a power cycle to reset, which improves safety but complicates user experience. However, the VIPER35LDTR’s hiccup mode can cause audible noise in the transformer during cycling, and its response time (~5 µs) is slower than the ICE2QR’s cycle-by-cycle limiting. If your application demands silent operation or ultra-fast protection (e.g., motor drive), consider adding an external latch circuit or selecting a controller with adaptive blanking time to avoid nuisance tripping.
In a space-constrained 22W flyback design with limited PCB area, what layout practices are essential to prevent instability and ensure the VIPER35LDTR operates reliably at its 136 kHz switching frequency?
To ensure stability and reliability with the VIPER35LDTR in tight layouts, minimize the high-di/dt loop formed by the input capacitor, MOSFET drain, and transformer primary—keep this loop <1 cm² to reduce parasitic inductance and ringing. Place the Vcc decoupling capacitor (100 nF ceramic) within 3 mm of pins 5 and 6, and avoid routing sensitive feedback traces (e.g., optocoupler collector) parallel to the drain node, as capacitive coupling can induce false triggering. Use a single-point ground for the control section and connect it to the input capacitor’s negative terminal. Without these practices, you risk subharmonic oscillation, increased EMI, or premature over-temperature shutdown due to reflected ringing stressing the internal switch.
Quality Assurance (QC)
DiGi ensures the quality and authenticity of every electronic component through professional inspections and batch sampling, guaranteeing reliable sourcing, stable performance, and compliance with technical specifications, helping customers reduce supply chain risks and confidently use components in production.
VIPER35LDTR CAD Models
STMicroelectronics VIPER35LDTR PCB symbols & footprints
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